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| author | Andrew Jones <drjones@redhat.com> | 2020-08-04 19:06:00 +0200 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2020-08-21 14:04:14 +0100 |
| commit | 2dbd780e34ac53e79c6c359ce12b89ed665ef562 (patch) | |
| tree | 6cf98418dfa7d1f93a3888324920e8a68b56259d /arch/arm64/kvm | |
| parent | 38480df564cc68f081bb38998927d164b9010995 (diff) | |
| download | linux-2dbd780e34ac53e79c6c359ce12b89ed665ef562.tar.gz linux-2dbd780e34ac53e79c6c359ce12b89ed665ef562.tar.xz | |
KVM: arm64: pvtime: Fix potential loss of stolen time
We should only check current->sched_info.run_delay once when
updating stolen time. Otherwise there's a chance there could
be a change between checks that we miss (preemption disabling
comes after vcpu request checks).
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200804170604.42662-3-drjones@redhat.com
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/pvtime.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index c3ef4ebd6846..95f9580275b1 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -13,6 +13,7 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; + u64 last_steal = vcpu->arch.steal.last_steal; u64 steal; __le64 steal_le; u64 offset; @@ -24,8 +25,8 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) /* Let's do the local bookkeeping */ steal = vcpu->arch.steal.steal; - steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal; - vcpu->arch.steal.last_steal = current->sched_info.run_delay; + vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); + steal += vcpu->arch.steal.last_steal - last_steal; vcpu->arch.steal.steal = steal; steal_le = cpu_to_le64(steal); |